1. Field of the Invention
The present invention relates to an opening/closing apparatus for a small door mounted at an electrical/electronic apparatus, and more particularly to an exhaust door opening/closing apparatus for facilitating discharging heat out of a projector. Specifically, the present invention relates to an automatic door mechanism for a slim type wall-hanging or stand-up beam projector.
2. Description of the Related Art
Recently, distribution of projectors capable of obtaining image information via a large screen is suddenly increased in order to satisfy demands of consumers as broadcasting via high definition televisions are thriving and markets of home theater system are expanded.
As typical examples of projectors, beam projectors widely utilized for presentation by being connected, for example, to a computer have been widely marketed and already become popular. These types of beam projectors are operated in such a manner that an image matrix is projected with a light source onto a large scale screen by micro mirrors (Digital Mirror Devices, DMDs), or by Liquid Crystal Devices (LCDs) in a fixed-in-space projection beam.
As illustrated in FIG. 1, a desk-top beam projector is the main stream for the conventional beam projector in which the projector is set in and supported by a pad such as a table. The desk-top beam projector as shown in FIG. 1 is manufactured in a rectangular box-type cradle of an external casing 10 in which components including a light source, an optical system (not shown) and a projection lens unit 11 are housed.
The beam projector adopts as a light source a high voltage discharging lamp, for example, a mercury lamp, a xenon lamp or a metal halide lamp such that it is inevitable to emit high temperature driving heat. As a result, radiant heat dischargers are needed. As illustrated in FIG. 1, a plurality of radiator grilles 12 capable of ventilating air are disposed at various locations of the external casing 10. Consequently, the conventional beam projector is structured in such a manner that an air discharge structure dissipating high temperature driving heat via radiant heat dischargers such as the radiator grilles 12 is disposed directly about a user.
There is a disadvantage in this type of air discharge structure according to the conventional method as described in that an increase of the driving time of a beam projector causes a temperature rise in ambient air of an interior space such that a periodical ventilation is needed which decreases the operating efficiency and simultaneously leaves a user in poor surroundings.
In an effort to avoid the disadvantage, attempts have been vigorously made to develop slim external casing beam projectors so that they can be hung up on a wall or stood up just like flat panel LCD (Liquid Crystal Display) TV or Plasma Display Panels (PDPs).
However, problems still exist in that it is difficult for the slim type beam projectors to secure enough inner space in the external casing, causing inconvenience in arranging components inside the casing, and designing and manufacturing discharge structures for effective release of the driving heat. Accordingly, mechanism development of discharge structure capable of effectively discharging driving heat of the slim type beam projector is demanded in earnest.